Device and method for aligning disk-shaped substrates

ABSTRACT

The invention relates to a simple and cost-effective method for aligning substrates. In order to achieve this, the invention provides a device for aligning disc-shaped substrates, in particular semiconductor wafers, comprising an alignment detection unit, at least one first support for receiving the substrate, which forms an oblique plane in relation to the horizontal, a stop against which the substrate can be displaced as a result of the oblique angle and a rotational device for rotating the substrate. The invention also relates to a method for aligning disc-shaped substrates, in particular semiconductor wafers, comprising the following steps: displacement of the substrate into an oblique position in relation to the horizontal, in which the substrate is held on a support which forms a tilted plane in relation to the horizontal and lies against a stop as a result of the oblique angle; rotation of the substrate into a predefined rotational position; and monitoring of the rotational position using a detection unit.

[0001] The present invention relates to an apparatus and a method forthe alignment of disk-shaped substrates, especially semiconductorwafers, and includes an alignment detection unit.

[0002] In the semiconductor industry, to manufacture semiconductorelements generally semiconductor disks, also known as wafers, that arecomprised of a single crystal, are subjected to various treatmentprocesses. These treatment processes are greatly automated, and betweenthe treatment processes the semiconductor disks are transported withhandling devices, which are generally support plates. In thisconnection, a centered placement of the disks upon the support plates isimportant in order to ensure a proper positioning of the disks in thevarious treatment devices. In addition, the disks must be aligned inaccordance with the axes of their crystal lattices. Both the centeringas well as the alignment of the disks is undertaken by alignmentapparatus, which are also designated as aligners.

[0003] With one known aligner, which is shown by way of example in FIGS.11a-d, a semiconductor disk 1 is deposited by a handling device 2 uponsupport pins 3 of the aligner. The handling device is subsequently movedout of the region below the wafer and the pins 2 are lowered, as aresult of which the disk is positioned upon the rotary turntable 4,which is designated as a chuck. The rotary turntable 4 is provided withan underpressure suction device in order to securely hold the diskthereon. If the disk 1 is attached by suction, the rotary table 4 isrotated about its axis of rotation. During this rotation, a lateraldisplacement of the disk relative to the axis of rotation is measuredwith a camera 5. The pins 3 are again raised in order to raise thesemiconductor disk 1 from the rotary table 4, and the pins are moved ina horizontal direction as a function of the measured displacement inorder to center the disk relative to the rotary table 4. Subsequently,the disk is again deposited upon the rotary turntable 4 in order torepeat the above measurement process and to ensure that the disk 1 isnow centered relative to the rotary turntable 4. This process isrepeated until a complete centering is achieved.

[0004] In addition to the measurement of the lateral displacement, thecamera 5 is in a position to recognize a marking in the form of arecess, which is also known as a notch, or to recognize a flattenedportion of the edge of the disk 1, which is also known as a flat, withthe notch or flat providing the crystal direction of the disk. After theaforementioned centering, the rotary turntable 4 is rotated in a desireddirection in order to bring the marking into a predetermined position.The positioning is monitored by the camera, which then alsosimultaneously reads the ID number that is formed in the semiconductordisk and that has, for example, the form of a barcode or a numbersequence.

[0005] The alignment process described above is very complicated andexpensive, and since it includes a plurality of steps that are to berepeated, it is also very time intensive, which results in a very lowthroughput. Furthermore, a comprehensive software is necessary for thecontrol of the various elements, and also a suction device is necessaryfor holding the disks on the rotary turntable, which unnecessarilyincreases the cost for the apparatus.

[0006] Due to mechanical movements of motors or other components of theunit, resonance effects that produce vibrations can occur, due to whicha disk that rests upon the pins can be shifted and can thus influencethe centering. A further problem results due to the suction of the waferagainst the rotary turntable, since as a consequence dust particles thatare in the environment can be suctioned on and which collect on thesurface of the wafer over a large surface area thereof in the region ofthe suction openings, as shown in FIGS. 12a and 12 b.

[0007] Contaminations of this type can, however, greatly adverselyaffect the usability of the semiconductor disk.

[0008]FIG. 12a shows the underside of a semiconductor disk 1 before itis suctioned onto a rotary turntable, and FIG. 12b shows the surface ofthe wafer after the suctioning onto the rotary turntable. As can be seenin FIG. 12a, a small amount of contamination is found on the undersideof the wafer and is distributed over the entire surface. However, as canbe recognized in FIG. 12b, due to the suctioning of the semiconductordisk a large number of particles collect on the underside, and inparticular in the region in which the suction device of the rotaryturntable suctions the disk 1.

[0009] DE-A-35 06 782 discloses an apparatus for the alignment of theedges of a wafer, according to which the wafer is again positioned on arotary turntable. The rotary turntable has an underpressure suctiondevice in order to securely hold the disk thereon. During the time thatthe disk is suctioned on, the rotary turntable is rotated about its axisof rotation, and a lateral displacement of the disk relative to the axisof rotation is measured with the aid of a series of photo detectors inorder to be utilized for the subsequent centering of the wafer.

[0010] U.S. Pat. No. 3,982,627 describes an apparatus for the automaticalignment of a wafer, according to which the wafer is placed upon aninclined support. Due to the incline, the wafer slides against arotatable abutment. For the alignment of the wafer, the rotatableabutment, and hence the wafer, are rotated until the wafer achieves adesired position. During the rotation of the wafer, it is held spacedfrom the support via an air cushion.

[0011] Proceeding from the previously described apparatus, it is anobject of the present invention to provide an apparatus and a method forthe alignment of disk-shaped substrates, in particular semiconductorwafers, which use an alignment detection unit and which, in a simple andeconomical manner, enable an alignment of the substrate and permit asimple integration into existing wafer treatment units. In thisconnection, an alignment involves not only a spatial arrangement butalso a certain rotational arrangement of the substrate.

[0012] Pursuant to the invention, this object is realized with anapparatus of the aforementioned type by means of at least one movablefirst support, which forms a support plane, for receiving the substrate,a device for tilting the first support relative to the horizontal inorder to bring the support plane into an inclined position relative tothe horizontal, an abutment against which the substrate is movable dueto the incline, and a rotation device for rotating the substrate. Themovable first support enables a depositing and a removal of thesubstrate in an essentially horizontal position as a result of which theapparatus can be easily integrated into existing systems in whichhandling devices generally hold the substrates in horizontal positions.It is therefore not necessary to alter the previously used handlingdevices. Due to the inclined support, the substrate is automaticallymoved into a spatially fixed position against the abutment. Due to therotation device, the substrate can now be moved into a prescribedrotated position, which is detected by the alignment detection unit. Thepositioning and alignment are effected in a single step and require nocomplicated control of various elements. Therefore, a suctioning of thesubstrate is not required, since a lateral sliding during the rotationis not possible due to the inclined position and the abutment. As aresult, the cost and problems associated with the suction device areeliminated.

[0013] The first support preferably has at least two first supportelements that form the plane and that enable as free a movement aspossible of the handling device for the loading and removal of thesubstrate. In this connection, preferably three first support elements,which form a three-point support, are provided. In order during arelative movement between the support elements and the substrate toprevent damage to the substrate and to prevent the production ofparticles, the support elements, at least in the support region, areprovided with a material having low friction, especially Teflon. Damageto the substrate during a relative movement between the support elementsand the substrate can preferably also be avoided by rounding off thesupport region of the support elements.

[0014] For a good guidance and to avoid a relative movement between thesubstrate and the abutment during the tilting of the first support, theabutment is preferably also tiltable. The abutment preferably has atleast two abutment pins that are spaced from one another in order to atleast partially receive the substrate therebetween and to ensure a fixedspatial positioning of the substrate.

[0015] Pursuant to a particularly preferred embodiment of the invention,at least one of the abutment pins is rotatable, as a result of which thesubstrate resting thereagainst can be rotated in a particularlystraightforward manner. For a good and uniform rotation of thesubstrate, and to avoid relative movements between the abutment pins andthe substrate, the abutment pins are preferably rotatable synchronouslyrelative to one another. This is preferably achieved by means of acommon drive element, such as, for example, a common drive belt that isin engagement with the abutment pins.

[0016] In order to enable a precise alignment of in particular a crystaldirection of the substrate, the rotation device can be controlled as afunction of an alignment determined by the detection unit.

[0017] Pursuant to a particularly preferred embodiment of the invention,the support elements and/or the abutment pins are disposed on a commonplate, which is preferably tiltable.

[0018] Pursuant to a further embodiment of the invention, the apparatushas a second support, which forms an essentially horizontal plane, forreceiving the substrate. In this connection, the first and the secondsupports are preferably movable relative to one another in order totransport the substrate from one support to the other, and to bring thesubstrate in particular out of a horizontal position into an inclinedposition. The second support preferably has at least two second supportelements that form the horizontal plane and that preferably have roundedsupport surfaces in order during a relative movement between substrateand support elements to avoid damage to the substrate against edges ofthe support elements.

[0019] Pursuant to a straightforward embodiment of the invention, thesecond support elements are embodied to be stationary. In thisconnection, the second support elements preferably extend throughopenings in the plate on which the first support elements and/orabutment pins are mounted.

[0020] Pursuant to an alternative embodiment, the second supportelements are movable with the plate and relative to it in order duringthe tilting of the plate to enable a transfer of the substrate from thesecond support elements to the first support elements and vice versa,with as low a level of relative movement as possible between thesubstrate and the second support elements. Furthermore, in this way itis possible to achieve that the support surfaces of the second supportelements always extend essentially parallel to a support surface of thesubstrate. In this connection, the support elements are preferablybiased in a direction away from the substrate.

[0021] In order to enable an automatic adaptation of the alignmentapparatus to substrates having different diameters, the apparatus ispreferably provided with a device for measuring the substrate diameter.The spacing between the abutment pins is preferably adjustable as afunction of the substrate diameter in order in this way to achieve aprecise positioning of the center point of the substrate that remainsuniform for substrates having different diameters.

[0022] Pursuant to one embodiment of the invention, in order to providea rotation of the substrate the first support elements are rotatableabout a common center point that preferably coincides with the centerpoint of the wafer. Due to a rotation of the first support elements, arelative movement between the substrates and the support elements isavoided during the rotation, thereby reducing the danger of damage tothe substrate. In this connection, the first support elements arepreferably disposed on a rotatable element.

[0023] Where substrates having different substrate diameters arepresent, the center point of the substrate is positioned in differentlocations during the alignment to the extent that a uniform positioningof the center point via an adjustment of the abutment pins as a functionof the substrate diameter is not effected. In order therefore to ensurea centered accommodation of the substrate upon a substrate-handlingdevice after the alignment, pursuant to one embodiment of the inventionthe movement of the handling device is controlled as a function of thesubstrate diameter.

[0024] Pursuant to a further embodiment of the invention, a centeringbetween substrate and handling device is achieved by a unit for thesynchronous movement of the first or second support as a function of thesubstrate diameter. In so doing, after the tilting back of the firstsupport a precise positioning of the substrate center point, whichremains uniform for substrates having different diameters, is achievedso that a special control of the handling device is eliminated.

[0025] The object of the present invention is also realized by a methodof aligning disk-shaped substrates, in particular semiconductor wafers,by depositing the substrate upon an alignment apparatus, moving,especially tilting, a movable first support of the alignment apparatusinto a position that is inclined relative to the horizontal in order tobring the substrate into a position that is inclined relative to thehorizontal and due to the incline to bring the substrate against atleast one abutment, and rotating the substrate into a predeterminedrotated positioned that is monitored by a detection unit. This resultsin the advantages already mentioned in conjunction with the apparatus,and in particular a straightforward and economical alignment ofsustrates in a time saving, single sequence of steps. By moving,especially tilting, the support, the substrate can initially bedeposited on the alignment apparatus in an essentially horizontalposition, as was the case with the previous apparatus. This results in agood compatibility of the inventive method with existingsubstrate-handling devices for the transport of the substrate.

[0026] To ensure a good guidance of the substrate, and to reduce arelative movement between the substrate and other elements, the supportand the abutment are preferably moved in common.

[0027] For a simple rotation of the substrate, it is preferably rotatedby rotating at least one abutment element of the abutment. In thisconnection, for as uniform a rotation as possible, preferably twospaced-apart abutment elements are rotated.

[0028] The rotation of the substrate is preferably controlled as afunction of an alignment of the substrate determined by the detectionunit in order to ensure a proper and precise positioning of thesubstrate in the direction of rotation.

[0029] The diameter of the substrate is advantageously determined, andpursuant to a preferred embodiment of the invention the spacing betweenthe abutment elements is adjusted as a function of the diameter. Thisenables a precise and uniform positioning of a center point of thesubstrate independently of its diameter. In order to avoid a relativemovement between the substrate and the support, the substrate ispreferably rotated by means of a rotation of the support.

[0030] Pursuant to one embodiment of the invention, the movement of asubstrate-handling device is controlled as a function of the diameter ofthe substrate in order to ensure a centered accommodation of thesubstrate. Pursuant to a further embodiment, the centered accommodationis achieved by synchronously moving the support elements of the first orof the second support in one direction, as a function of the substratediameter, after the tilting back of the first support.

[0031] Further features, advantages and details of the invention will beexplained subsequently with the aid of embodiments with reference to thefigures. The drawings show:

[0032]FIGS. 1a and b a schematic side view as well as a top view upon anapparatus pursuant to the present invention;

[0033]FIGS. 2a and b a schematic side view as well as a top view similarto FIG. 1, with a semiconductor wafer placed upon the apparatus;

[0034]FIG. 3 a schematic side view of the apparatus of FIG. 2a in astarting position;

[0035]FIG. 4 a schematic side view of the apparatus of FIG. 3 in asecond, tilted position;

[0036]FIG. 5 a top view upon the apparatus in its tilted position;

[0037]FIG. 6 a schematic illustration of semiconductor substrates havingdifferent diameters, as they rest against a non-movable abutment of theinventive apparatus;

[0038]FIG. 7 a schematic illustration of semiconductor wafers havingdifferent diameters, as they rest against a movable abutment pursuant tothe inventive apparatus;

[0039]FIG. 8 an enlarged illustration of an inventive apparatus pursuantto FIG. 1;

[0040]FIG. 9 a schematic side view of an alternative embodiment of analignment apparatus pursuant to the present invention;

[0041]FIG. 10 a schematic side view of an apparatus pursuant to FIG. 9in a tilted position;

[0042]FIGS. 11a-d schematic side views of a conventional alignmentapparatus illustrating the operating sequence of the apparatus;

[0043]FIG. 12 the results of a surface scanning prior to and after analignment process on the conventional alignment apparatus.

[0044]FIGS. 1a and 1 b show a schematic side view and a top viewrespectively of an apparatus 10 for the alignment of disk-shapedsemiconductor wafers 12 (see FIG. 2). The apparatus 10 has a plate 14which, as will be described subsequently, can be tilted. The plate 14has three oval openings 16 that extend upwardly from below through theplate 14. Three support pins 18 extend through the openings 16 in theplate 14 and are secured to a non-illustrated base plate. The supportpins 18 form a three-point support having an essentially horizontalsupport plane for receiving the semiconductor wafer 12, as can be bestseen in FIG. 2a. Disposed on an upper side 20 of the plate 14 are threeTeflon disks 22 which, as will be described subsequently, serve assupport elements for the semiconductor wafer 12 when the plate 14 istilted relative to the horizontal. Instead of the three pins 18 and thethree disks 22, it is also possible to respectively provide twoelongated elements that form a support plane and permit a reliablesupport of the wafer.

[0045] Furthermore provided on the plate 14 are two rotatable abutmentpins 24. The abutment pins 24 are rotatable via a non-illustrated drivemechanism, whereby the two pins are interconnected via a common drivebelt to achieve a synchronous rotation of the two pins.

[0046]FIG. 3 shows a schematic side view of the apparatus 10 with awafer 12 placed thereon in a starting position. The wafer 12 rests uponthe support pins 18, and the plate 14 has a horizontal orientation.

[0047]FIG. 4 shows the apparatus 10 in a different position. The plate14 is tilted relative to the horizontal, so that the wafer 12 no longerrests upon the stationary support pins 18, but rather upon the Teflondisks 22 and is therefore also in an inclined position. Due to theincline, and as a result of the fact that Teflon has a low frictionalresistance, the wafer 12 slides against the abutment pins 24 and iscentered between them, as can be best seen in the top view of FIG. 5. Inthis position, the abutment pins 24 are rotated in order to rotate thewafer 12 about its central axis, as can also be best seen in the topview of FIG. 5.

[0048] It is known that semiconductor wafers generally have a mark,which is also known as a notch, or a flattened portion, which is alsocalled a flat, with the aid of which the crystal direction of the wafercan be determined. The apparatus 10 has a non-illustrated sensor device,such as, for example, a camera or a CCD array or image sensor that is inthe position to recognize a marking of the wafer and to determine theposition thereof during the aforementioned rotation of the wafer aboutits central axis. In order to achieve a desired crystal alignment of thewafer 12, its rotation is controlled in such a way that the marking ofthe wafer is rotated into a predetermined position that is recognized bythe sensor device. The rotation is therefore controlled with the aid ofthe position of the marking determined by the sensor.

[0049] If the marking is in the predetermined position, thesemiconductor wafer is aligned not only spatially but also relative toits crystal direction. The plate 14 is now tilted back, as a result ofwhich the wafer 12 is again placed upon the support pins 18. The wafer12 is now disposed in a precisely determined position upon the supportpins 18 that is also aligned relative to its crystal direction. For theremoval of the substrate 12, a substrate-handling device is moved underthe wafer 12 in such a way that it receives the wafer in a centeredmanner and transports it away for the further processing.

[0050] With the previously described embodiment, the abutment pins 24are locally fixed upon the plate 14. If semiconductor wafers havingdifferent diameters are placed upon the apparatus 10 and aresubsequently aligned, the center point of the respective wafer islocated at different positions, as can be seen from FIG. 6. With wafershaving smaller diameters, the center point of the wafers approachescloser to a straight line A that passes through the abutment pins 24.

[0051] In order to precisely determine the diameter of the wafer, andhence its center point, after the orientation, a sensor for themeasurement of the wafer diameter is provided. This function is carriedout by the alignment sensor, i.e., for example, by a camera or CCD arrayor image sensor. A length scale on the plate 14 is read by the camera orCCD array or image sensor, as a result of which the wafer diameter isknown. The movement of the handling device for the removal of thesemiconductor wafer is controlled as a function of the thus-determineddiameter, so that it always receives the wafer in a precisely centeredmanner. Of course, other ways for determining the wafer diameter arealso possible.

[0052]FIG. 7 schematically shows an alternative embodiment of theinvention, according to which essentially the same components areprovided as with the first embodiment. Instead of a pair of laterallyfixed abutment pins 24, the abutment pins 24 are mounted on the plate 14so as to be laterally movable. As a result of a lateral movement of theabutment pins 24 out of the first position shown in FIG. 7, which isillustrated by a filled-in point, to a second position, which isillustrated by a circle, it is possible to receive semiconductor wafershaving different diameters in such a way that their center point alwayslies in the same position. For this purpose, it is again necessary todetermine the diameter of the wafer and subsequently to move theabutment pins laterally so that the center point of the substrate restsupon a predetermined point. This results in the advantage that thesubstrate-handling device can always be moved into the same position,independently of the wafer diameter, in order to receive the wafer in acentered manner. Furthermore, this enables a centering of the waferrelative to the Teflon supports 22 independently of the wafer diameter.In this connection, it is possible to arrange the Teflon supports 22 insuch a way that they lie upon a circle, the center point of whichcoincides with the center points of the wafers. Since the Teflonsupports are disposed upon a rotatable element, such as, for example, arotary turntable or a rotatable circular ring, the rotation of thewafer, and hence the alignment of the wafer relative to the notch orflat, can be effected via the Teflon disks. In this way, in particularfriction between the Teflon disks and the wafer is avoided, since norelative movement between the wafer and the disks occurs during therotation.

[0053] For a centering of the wafer relative to a handling deviceindependently of its diameter, it is also possible to linearly move thesupport pins 18 or the Teflon disks 22, i.e. the tilt plate.

[0054] In a further embodiment, the centered accommodation is achievedby synchronously moving the support elements of the first or the secondsupport in one direction, as a function of the substrate diameter, afterthe tilting back of the first support.

[0055]FIG. 8 shows how the plate 14 of the apparatus 1 of FIG. 1 istilted back after an alignment process. In the position shown in FIG. 8,the wafer 12 is partially accommodated on one of the support pins 18 andpartially upon one of the Teflon disks 22. In this connection, duringthe tilting movement of the plate 14 a relative movement occurs betweenthe encircled edge of the support pin 18 as well as the encircled edgeof the Teflon disk 22, since the wafer is pressed toward the right bythe abutment pins 24. This can lead to undesired particle formation aswell as scratching of the wafer surface.

[0056] Therefore, with a non-illustrated preferred embodiment of theinvention, the edges of the support pins 18 as well as of the Teflondisks 22, or of their entire support surface, are rounded off, therebyachieving a rolling of the wafer on the pins and disks. In particular,scratching due to the edges of the support pins and of the Teflon disksis avoided.

[0057]FIGS. 9 and 10 show an alternative apparatus 30 for the alignmentof semiconductor wafers 32. The apparatus 30 has a base plate 34 and atilt plate 36, which are pivotably interconnected by a swivel connection37.

[0058] As with the first embodiment, rotatable abutment pins 38 aremounted on the tilt plate 36 and are rotatable about their central axisvia a non-illustrated device. First support pins 40 as well as secondsupport pins 42 are furthermore disposed on the tilt plate 36. Threefirst and three second support pins 40,42 are provided, whichrespectively form a three-point support for the semiconductor wafer 32.

[0059] The support pins 40 extend through the tilt plate 60 and aremovable relative to the tilt plate 36. The movement of the support pins40 relative to the tilt plate 36 is limited by an upper and a lower stopor limit disk 44,46 that is disposed above or below the tilt plate 36respectively. Disposed between the lower limit disk 46 and an undersideof the tilt plate 36 is a spring 48 that biases the support pin 40downwardly, i.e. away from the semiconductor wafer 32. The support pin40 has a base or foot 50 that in a first position of the tilt plate 36,as shown in FIG. 9, is in contact with an upper side of the base plate34, and presses the support pin 40 upwardly against the bias or tensionof the spring through the plate 36. In this first position that isillustrated in FIG. 9, the support pins 40 form an essentiallyhorizontal support plane that lies above a support plane formed by thesupport pins 42.

[0060] If the tilt plate 36 is tilted relative to the base plate 34, thefeet 50 of the support pins 40 move away from the upper side of the baseplate 34, and the support pins 40 move away from the substrate due tothe bias of the spring. This movement is limited by the upper limit disk44, as can be seen in FIG. 10. In this position, the support planeformed by the support pins 40 lies below the support plane formed by thesupport pins 42, so that the substrate now rests upon the support pins42. In this position, the wafer 32 slides against the abutment pins 38and, as with the first embodiment, is centered between them and isaligned as described previously.

[0061] After the alignment, the plate 36 is tilted back, as a result ofwhich the feet 50 or the support pins 40 come into engagement with thebase plate 34, and the pins press against the bias of the spring in thedirection of the semiconductor wafer 32. The feet 50 of the support pins40 are rounded off so that during the tilting back they roll upon thebase plate and prevent a canting of the pins within the tilt plate 36.Since the support pins 40 are tilted along with the tilt plate 36, theirsupport surfaces are always parallel to the wafer surface, therebyessentially precluding a placement of the wafer upon only one pin edgeas well as a relative movement between the support pins 40 and the wafer32 during the tilting back.

[0062] Although the invention was described with the aid of preferredembodiments, the present invention is not limited thereto. Inparticular, it is possible to eliminate the support pins 18 and 40 ofthe embodiment, as a result of which the semiconductor wafer would beplaced directly upon the Teflon disk 22 or upon the support pins 42. Itis also not absolutely necessary to provide a tiltable plate. Aninclined support plane can also be achieved by a relative movement in avertical direction between the support elements. It is furthermore alsopossible to place the semiconductor wafers upon a stationary supportdevice that forms a plane that is inclined relative to the horizontal.In this case, it would be necessary to provide a wafer-handling devicethat brings the wafers into the inclined position and deposits them uponthe support device. The problem of particle accumulation upon the waferis reduced in that a particle-suction device is provided that inparticular in the tilted state of the plate suctions off particles foundon the wafer in a downward direction.

1. Apparatus (10;30) for the alignment of disk-shaped substrates(12;32), especially semiconductor wafers, with an alignment detectionunit, characterized by at least one movable first support (22;42) forthe accommodation of the substrate (12;32), which forms a support plane;a device (14;36) for the tilting of the first support (22,42) relativeto the horizontal in order to bring the support plane into a positionthat is inclined relative to the horizontal; an abutment (24;38) againstwhich the substrate is movable due to the incline; and a rotation device(24;38) for the rotation of the substrate.
 2. Apparatus according toclaim 1, characterized in that the first support (22;42) has at leasttwo first support elements (22;42) that form the plane.
 3. Apparatusaccording to claim 2, characterized in that the first support elements(22;42) are provided at least in the support region with a materialhaving low friction, especially Teflon.
 4. Apparatus according to claim2 or 3, characterized in that the support region of the support elementsis rounded off.
 5. Apparatus according to one of the preceding claims,characterized in that the support (24;38) is tiltable.
 6. Apparatusaccording to one of the preceding claims, characterized in that theabutment (24;38) has at least two abutment pins (24;38) that are spacedfrom one another.
 7. Apparatus according to claim 6, characterized inthat at least one of the abutment pins (24;38) is rotatable. 8.Apparatus according to claim 7, characterized in that the abutment pins(24;38) are rotatable synchronously relative to one another. 9.Apparatus according to one of the preceding claims, characterized inthat the rotation device (24;38) is controllable as a function of analignment of the substrate (12;32) determined by the detection unit. 10.Apparatus according to one of the preceding claims, characterized inthat the support element (22;42) and/or the abutment pins (24;38) aredisposed on a common plate (14;36).
 11. Apparatus according to claim 10,characterized in that the plate (14;36) is tiltable.
 12. Apparatusaccording to one of the preceding claims, characterized by a secondsupport (18;40) which forms an essentially horizontal plane for theaccommodation of the substrate.
 13. Apparatus according to claim 12,characterized in that the first support (22;42) and the second support(18;40) are movable relative to one another.
 14. Apparatus according toclaim 12 or 13, characterized in that the second support (18;40) has atleast two second support elements (18;40) that form the horizontalplane.
 15. Apparatus according to claim 14, characterized in that thesecond support elements (18;40) are embodied to be stationary. 16.Apparatus according to claim 14 or 15, characterized in that the secondsupport elements (18;40) extend through openings in the plate (14;36).17. Apparatus according to claim 14 or 16, characterized in that thesecond support elements (40) are movable together with the plate (36)and relative to it.
 18. Apparatus according to claim 17, characterizedin that the second support elements (40) are biased in a direction thatfaces away from the substrate.
 19. Apparatus according to one of thepreceding claims, characterized by a device for the measurement of thesubstrate diameter.
 20. Apparatus according to one of the precedingclaims, characterized in that the spacing between the abutment pins(24;38) is adjustable as a function of the substrate diameter. 21.Apparatus according to one of the preceding claims, characterized inthat the first support elements (22;42) are rotatable about a commoncenter point.
 22. Apparatus according to one of the preceding claims,characterized in that the first support elements (22;42) are disposed ona rotatable element.
 23. Apparatus according to one of the precedingclaims, characterized by a substrate-handling device for the transportof the substrate (12;32), whereby the movement of the handling device iscontrollable as a function of the substrate diameter.
 24. Apparatusaccording to one of the preceding claims, characterized in that thefirst (22;42) and/or the second support elements (18;40) aresynchronously movable in one direction as a function of the substratediameter.
 25. Method for the alignment of disk-shaped substrates,especially semiconductor wafers, with the following method steps:placing the substrate upon an alignment apparatus; moving, especiallytilting, a movable first support of the alignment apparatus into aposition that is inclined relative to the horizontal for the movement ofthe substrate into a position that is inclined relative to thehorizontal and in which the substrate rests against at least oneabutment due to the incline; rotating the substrate into a predeterminedrotated position; and monitoring the rotated position with a detectionunit.
 26. Method according to claim 25, characterized in that thesupport and the abutment are moved in common.
 27. Method according toone of the claims 25 or 26, characterized in that the substrate isrotated by rotating at least one abutment element of the abutment. 28.Method according to claim 27, characterized in that at least twospaced-apart abutment elements are rotated.
 29. Method according to oneof the claims 25 to 28, characterized in that the rotation of thesubstrate is controlled as a function of an alignment of the substratedetected by the detection unit.
 30. Method according to one of theclaims 25 to 29, characterized in that the diameter of the substrate isdetermined.
 31. Method according to claim 30, characterized in that thespace between the abutment elements is adjusted as a function of thediameter of the substrate.
 32. Method according to one of the claims 25to 31, characterized in that the substrate is rotated by a rotation ofthe support.
 33. Method according to claim 30, characterized in that themovement of a substrate-handling device is controlled as a function ofthe diameter of the substrate.
 34. Method according to claim 30,characterized in that the first and/or the second support elements aresynchronously moved in one direction as a function of the substratediameter.